My only recommendation to a first-timer (as I posted on another thread a few days ago) is to avoid making your diorama cluttered with unnecessary figures and accessories.
Best advice to to take a good look at some period photos of your subject to get some ideas of a "typical" airfield setting and let your diorama tell a plausible story. For example, if your model doesn't have the engine cowl removed, fuel cap open or gun access hatches open, then it obviously isn't being serviced, refuelled or re-armed, so there's little likelihood that there would be toolboxes, fuel drums or ammo boxes around.
Keep it simple. A nicely built model on just a basic, no-frills base can look as good as one with all panels removed and service personnel crawling all over it. Maybe just have a pilot or a couple of ground crew relaxing in the shade of the wing, taking a moment's peace from the stress of war.